1. Field of the Invention
The present invention relates to a brush holding device used in a motor, which includes a brush holding frame having a guide hole through which a flexible conductive member leading an electric current to or from a brush is drawn out, and a base plate onto which both sides of the lower portion of the brush holding frame is fixed. The present invention also relates to a method of assembling the brush holding frame onto the base plate in the brush holding device.
2. Description of the Related Art
A typical brush holding device used in a motor is disclosed, for instance, in FIGS. 1 to 3 of Japanese Utility Model Kokai Publication No. Hei. 3-18658. The device will be explained with reference to the FIGS. 10 and 11 attached hereto. In these Figures, reference numeral 1 designates a brush; 2, a brush holding frame for holding the brush; 3, a flexible conductive member, so called as a pig-tail, for leading an electric current to or from the brush; 4, a guide hole perforated through the holding frame so that the flexible conductive member is drawn out therefrom; 5, a base plate onto which the brush holding frame is fixed; 6, a fixing-purpose caulking pawl implanted on the base plate; and 7, a hole of a holding frame through which the caulking pawl is passed.
The brush holding device 2 shown in these Figures is designed to adopt a fixing method in which the bottom surface of the brush holding frame 2 is placed onto the base plate surface so that the caulking pawls 6 are upwardly inserted into the respective holes 7 provided on both sides of the lower portion of the brush holding frame 2, and then the caulking pawls 6 are bent or beaten appropriately to fix the brush holding frame 2 onto the base plate 5 by "caulking".
This fixing method or fixing structure may arise a problem in that a short circuit occurs by the contact between the flexible conductive member 3 and the caulking pawl 6 formed by raising up a portion of the base plate 5 made of a steel plate since the flexible conductive member 3 so called as a pig-tail is elongated above a fixing region where the caulking pawl 6 is caulked.
For this reason, an insulative tube 8 is additionally required and an assembler is forced to carry out such a work that the flexible conductive member 3 is at least partially covered by the insulative tube 8 over a lengthwise region contactable with the fixing region, which results in the cost increase.
Since the brush holding frame 2 is fixed by bending or caulking the caulking pawl 6 and the brush holding frame 2 of this kind is made of synthetic resin, the brush holding frame 2 or its fixing region may accidentally deformed or damaged during the fixing work by beating. On the other hand, if the assembler carries out the fixing work while trying to avoid such accident, another problem arises in that the installation inevitably becomes unstable and the required sure fixing can not be achieved. In addition, the brush holding frame is generally molded of high-insulative synthetic resin.